Process for the manufacture of aluminum chloride



M. M. HOLM June 28, 1932.

PRocEss FOR THE: MANUFACTURE oF ALUMINUM GHLORIDEv Filed sept. 2'?, 1927III ....,AtxLnQ kuh Q2 Patented June ze, 193,2

UNITED sTATEs mm I. HOIM, 0111' mrENf-rI OFFICE 1 GALIIONIA, ASSIGNOB T0STANDARD-OIL MI- PANYOF CALIFORNIA, BAN FBANUIBCO, GALIIOBNIA, ACORPORATION Olil DELL'- WARE rnocnss ron murac'runn or Immun snnunmn measeptember a7. isa?. semi In. aaams.

This invention relates tothe manufacture of aluminum chloride by thereaction of chlorine on a' mixture of carbonaceous material and finelydivided material containing aluminum. 5 An object nf this invention isto disclose n process of utilizing finely divided materials containingalumina in the manufacture of aluminum chloride. 1 Another object is toincrease the apparent density of finely divided aluminous materials torender them useful in the manufacture of aluminum chloride.

Another object is to disclose a process of making aluminum chloride fromvfinely dividf ed aluminous materials, particularly from the coke`resulting from aluminum chloride treatment of oils. 4

An object of the invention is to recover as the ash in petroleum coke.

Aluminum Ichloride is generally manufactured by contacting analumina-carbon mixture 'with chlorine gasat high temprature. Thealumina-carbon mixture may be a mechanical combination of'a naturalalumina such as bauxite and coke or coal, in which case the reactionwith chlorine is very slow, even if the solid materials are finelypowdered and intimately mixed, and temperatures up to 1800 F. are used.If bauxite and asphalt -20 aluminum chloride the aluminum content of arecoked to ther at temperatures in thel of 1800 F. an exceptionally'neighborh y reactive alumina-carbon mixture is obtained which rapidlcombines with chlorine at temperatures as ow as 950 F. to producealuminum chloride. The low reaction temperature may be maintained byexternally heating the chlorination apparatus or by controlling theintroduction of air when heat is supplied by internal combustion Vof .apart of the' carbon contained. By using lower-temperatures in thismanner to produce eiective chlorination the consumption of fuel isreduced and eiciency of the reaction improved.

If itis desired to supply external heat and I not depend onthe internalcombustion of carbon in the chlorination apparatus, it is possible tointroduce approximately the correctamount of carbon 1n thealumina-carbon mixture for the most eiiicient reaction. It has beenfoundthat some additional carbon over the theoretical requirement mustbe charged but the excess carbon must be limited or it will tend to maskor cover up a large part of the alumina and prevent its reaction withchlorine. The carbon content of the alumina-carbonl mixture should notexceed of the alumina content or the reactivity of thev mixture will beeatly impaired, and it should not be less titan 20% of the alumina orthe actual recovery will be reduced. The

same result may be obtained by internal combustion of ai portion of thecarbon in the mixture if due allowance for carbonto the consumed 4ismade in the amount of carbon introduced with the alumina-carbon mixture.

etroleum coke derived from the When residue 6 an aluminum chloridetreatment of oil is consumed in a gas producer or otherchlorine lump ofalumina coated with carbon woul react with chlorine gas under requiredtemperature conditions.v

to form'al'uminum chloride, but after the f contact therewith. E inegrnding'fof alunni-"1 nous materials, such as bauxite, clays, varin ousaluminum silicates and the like, reduces .g the apparent density ofthese materials. For

examp e, an alumlnous clay weighing 'l5 Reaction between the carbon,alumina and is rendered-more eicient when the alumma is in 'nely dividedform. It is conceivable that a lar lbs. per cu. ft./in Alarge lumps maywei h lbs. r cu. ft. when ound,and rovide a suita lemedium for clorination. owever,

lighter, more finely divided materialsare hard to handle in Vthemanufacture oalumi'- num chloride, as will be brought out more Whenalumina' ash or finely divided material containing alumina is'coked withthe proper amount of asphalt or heavy hydrol carbon to give a suitablecarbon content for chlorination a powder is produced, which thoughreactive in the presence of chlorine, has a'tendency to blow out of thechlorination apparatus along with the gases generated To insure propercirculation of chloriiie through the alumina-carbon mixture the powdermust be spread in thin beds, which with the low gas velocities necessarto prevent the powder blowing out woul require apparatus of uneconomicsize and impractical design. If a considerable excess of asphalt iscoked with the alumina a soft form of cokemay be produced which althoughavoiding the diiiiculties of powder is wasteful of asphalt andinellicient in its reacting eifect with chlorine. f

By the process of the present invention, I am enabled to produce fromalumina ash lor and asphalt a reactive mixture of proper alumina-carbonratio which can be treated in thick beds with chlorine gas at eliicientvelocities, so .that substantially the entire alumina content may beconverted to aluminum chloride and recovered. By -alumina ash is meant ainel ash composed lar e y of alumina, said ash being produced byconsuming petroleum coke or residue derived from aluminum chloridetreatment of oils in. a gas generator'or otherwise burning such residue.Although this invention is applicable to the utilization of any finelydivided material containing alumina, I will describe in detailapreferred method of utilizing an alumina ash and recovering the aluminain the form of aluminum chloride. The accomcall the various steps of theprocess and will ena le anyone acquainted with the art to f understandthe invention.'

Referring to the drawing, (1) represents a gas-producer or other devicein which coke containing alumina ash is consumed and from which the ashis're'covered. The alumina remaining as ash rvin '(1) is transported toa mixer (2) in which the alumina is'preferably mixed or contacted withwater to form a pasteY and thereafterdried in a suitable drier (3). 'Ihedried alumina paste is then carried to a 'nder (f1) in which it ispulverized and t en passed te a mixer (5). In v the mixer" (5) thealumina is. preferably olten asphalt in proportions to may be preferableto heat the mixture preinely divided material containing aluminadividedincombustibleV panying drawing illustrates diagrammati-V produce in thecoking process aratio of'about A l The alumina-asphalt mixture,I ischarged Y tda coke oven (6) and carbonizedfto coke by the application ofexternal heat. While thisl coking operation is shown as a single step itliminarily in steel apparatus to drive oli' most of the volatile matterat temperatures materially above the natural melting point of theasphalt but belowA the temperature for com-` plete carbonization, as forrinstance at a dull red heat. The preliminary coke, 'thus produced maythen be transferred to a coke oven lined with brick or other suitablematerial in which the coking is completed at tempera-fv turesaproximating 1800 F., such as correspond to a yellow or white heat.

One of the advantages of coking the alumina-carbon mixture in two steps,as described,

lies in the fact that the coke has a tendency i to adhere strongly tothe sides of the apparatus and if the retortis of metal the coke cannotbe freed from the walls without damaging the equipment. While thelpreliminary coking eliminates most of the volatile mat ter it isnecessary to complete the process at higher temperatures' than desirable.with steel apparatus, so the final step may be car- :xied out-in abrick lined oven. lThe material treated in the final step, however,having most of its original volatile'matter removed do'es not melt andtend to form an adhesive coke, and if broken up in suitable sizes, up yto say 3 inch lumps,after the first step, may b charged direct to thealuminum chloride producer without substantial loss of heat.

The alumina-carbon mixture produced in the coke oven (6) 'is conveyed toan aluminum chloride producer (7)where it iscontacted with chlorine gasand subjected to external heat. -The chlorine reactsl with thealumina-carbon mixture `at temperatures as low as about 950, F. to formvaporized llt aluminum chloride andixed gases which chloride iscondensed and recovered. v

The step of contacting the finely divided aluminous -material with aliquid has been found to increasethe apparent density of the material,even though the liquid is removed and the treated material ground ordisintegrated sufiicientlyto remove lumps, say50 mesh. For exam le, whenfinely divided' alumina ash weighlng about 10 lbs. per c u. ft.A wasmixed withwater, dried and ound, the resultingalumina weighed 26.8 1 percu.

pass to a condenser (8) where the aluminum` izo ft.. The coke producedby mixing this treat'- ed alumina with preferred amounts of asphalt andcarbonizing, was hard, dense and exceptionall suitable for theproduction of aluminum c' oride by exposure to chlorine at elevatedtemperatures. This reaction will proceed rapidly and eiiiciently attemperatures considerably below those at which mechanical mixtures ofalumina and carbon are reactive and while material amounts of aluminumchloride are produced at 950 F., for best results the process isoperated between 11007F. and 1650 F.

It is not known definitely why the steps of contacting a finely dividedmaterial with a 1i uid, removing the liquid and forming a co e from thetreated material results in such an'unexpected hard, dense coke, eventhough the treated material is ground after `contacting with a liquid.Water is preferred as the contacting liquid, however aqueoussolutions ofwell known coagulating agents, such as hydrochloric acid or sulphuricacid, or acid salts such'as aluminum sulphate, or solutions of sodiumsilicate may be used.

While the process herein described is well adapted to carry out theobjects of the present invention, it is understood that variousmodifications and changes may be made without departing from the spiritofthe invention and that the invention includes all such modificationsand changes as come within vthe scope of the following claims.

I claim: l

1. A method of producing a coke adapted forv use in the manufacture ofaluminum chlorideandvcontaining finely divided aluminous material,comprising contacting a finely divided aluminous material with anaqueous liquid, removing the liquid and coking a mixture of the treatedaluminous material with a heavy hydrocarbon.

2. A method of producing coke adapted for use in the manufacture ofaluminum Achloride and. containing finely divided aluminous material,comprising contacting a finely divided aluminous lmaterial with water,substantially removing the water and coking such treated aluminousmaterial with a carbonaceous material.

3. In -a method of manufacturing aluminum chloride, the steps ofcontacting a finely ldivided aluminousv material with water,

substantially removing the water, coking such treated aluminous materialwith a carbonaceous material and subjecting the resulting coke to theaction of chlorine at an elevated temperature.

4. In a method of manufacturing aluminum chloride, the steps ofcontacting a finely divided aluminous material with-water,-dry

' ing and disintegrating such materials, mixing such .treated aluminousmaterial with a heavy hydrocarbon, heating the mixture to eliminate asubstantial portion of volatiles,

further heating the mixture to form a coke and subjecting the coke tothe action of chlorine at an elevated tem erature.

5. A method. of pr for use in the manufacture o aluminum chloride andcontaining finely divided aluminous material, comprising contacting afinely divided aluminous material with water, removing the water, mixingthe treated aluminous material with a heavy hydrocarbon and cok'- ingthe mixture, the coke thus produced containing between fifteen andthirty-five per' cent carbon.

6. In a method of manufacturing aluminum chloride, the-steps ofcontacting a finely,

ucin acoke adapted l o divided aluminous material with water, ref movingthe water, mixing said treated material with an asphalticmaterial,subjecting the mixture to heat so as to eliminate a substantialportion of volatile matter, further heating the mixture to produce acoke, and

subjecting the coke to theaction of chlorine,-

the coke produced by this process containing two to five parts aluminato every part of carbon.

7. A method of manufacturing aluminum chloride comprising mixin akfinelydivided alumina ash with water, rying and disintegrating said ash,mixing the treated ash with an asphaltic material, heating thev in ixture so as to eliminate a' substantial portlon of volatiles, furtherheating the mixture so as' to coke the same and su jecting the coke tothe action of chlorineY at an elevated temmaterial with an asphalticmaterial, coking the mixture and subjecting the coke ,to the action ofchlorine at an elevated temperature to produce aluminum chloride.

10. A method of roducing a coke adapted for use in the manu acture ofaluminum chloride, comprising increasing' the apparent' vided aluminous'material with an aqueous' liquid, drying the finely divided material,

mixing the dried material, with a carbonaceous material, and then cokingthe mixture.

12. A method of manufacturing aluminum chloride comprising contacting afinely divided afuminous material with an aqueous liquid, drying thefinely divided aluminous material, mixing the dried material with acarbonaceous material, coking the mixture, and subjecting the coke tothe action of chlorine at an elevated temperature.

' Signed at Richmond, Cal.,this 15th day of September, 1927. MELVIN M.HOLM).

